1. Field of the Invention
The invention relates generally to electrical enclosures and, more particularly, to electrical bus assemblies for electrical enclosures.
2. Background Information
Electrical switching apparatus include, for example, circuit switching devices and circuit interrupters such as circuit breakers, contactors, motor starters, motor controllers and other load controllers.
Low voltage (e.g., without limitation, up to about 690 VAC; any suitable low voltage) circuit breakers, for example, which are used in power distribution systems, are commonly mounted, either alone or in combination with additional switchgear, within an electrical enclosure (e.g., without limitation, a load center; a switchgear cabinet). The circuit breakers are typically disposed within sections of the electrical enclosure, referred to as cells. The circuit breaker cells can be disposed beside, above, or below one another within the electrical enclosure.
Traditionally, electrical enclosures are limited to a single circuit breaker on a given branch circuit. This can make the intended goals of minimizing the overall size of the electrical enclosure and minimizing the amount and complexity of the electrical bus work of the electrical enclosure difficult. For example, FIG. 1 schematically shows an electrical enclosure 1 including a first circuit breaker 3 disposed horizontally beside a second circuit breaker 5. Specifically, the first circuit breaker 3 is disposed in a first cell 7 of the electrical enclosure 1 and the second circuit breaker 5 is disposed in an adjacent second cell 9. Thus, a barrier 11 is disposed between the first and second cells 7, 9, as shown. A first branch circuit 13, which branches off of a primary electrical bus 15 (e.g., trunk) supplies power to the first circuit breaker 3. Among the disadvantages of this configuration is that a separate, second branch circuit 17 is required to supply power to the second circuit breaker 5 within cell 9 of the electrical enclosure 1. Additionally, the barrier 11 (e.g., enclosure wall), which is disposed between first circuit breaker 3 and second circuit breaker 5, occupies valuable space within the electrical enclosure 1 and prevents the circuit breakers 3, 5 from being positioned as closely together as desired.
It will, therefore, be appreciated that prior proposals for positioning circuit breakers have required one of the following two compromises: (1) when the circuit breakers are disposed side-by-side in the same horizontal plane, two separate cells (e.g., first and second cells 7, 9) are required, each of which has a substantial width and requires its own branch circuit, thereby requiring the electrical enclosure to have an overall width that is much larger than desired; and (2) positioning the circuit breakers in different planes (e.g., without limitation, stacking the circuit breakers vertically). These limitations can, in large part, be attributed to the relatively large size of known electrical bus members and mandated clearance (i.e., minimum distance) requirements (phase-to-phase; phase-to-ground) of the circuit breaker.
There is, therefore, room for improvement in electrical enclosures and in electrical bus assemblies therefor.